Food fell into bottom of oven and now smokes

SOURCE: wall oven too hot,at 350

you need a new thermostat control. or purchase a small oven thermometer and us it to adjust/compensate the oven temp by lowering the setting to 300.
only other option is to purchase a new oven.
check with a local repair shop on price to install a new thermostat control unit. if the unit is over 10 years old, it would be more economical to replace the unit entirely.

SOURCE: blackened pans, high flames in oven even at 200 degrees

You still have not answered the questions I asked you, and you have posted your question under an electric range model. I will just have to guess and give you general info due to the lack of information you have given.
I will guess that you are using your range on LP gas. You don't compain of top burner performance, so I will take that to signify that the regulator has been changed from natural to LP, and that the burner orifices have been changed as well. That leaves only the oven. You need to find the spot where the gas comes out of the safety valve and travels up the venturi tube to the oven burner. There will be a small (about 3/4 inch square) adjustable air flow hole there, and right there you will see a brass collar. Use a 1/2 inch wrench to turn that brass collar three full turns clockwise. (it is usually easier to count 12 one quarter turns) If someone has tried to do this step, it may be part way turned in already, so you may not need to, or be able to, turn it three full turns. You do not want to turn it too far, but it will take a little effort. If flames are still too high, turn it a little more. Usually, the square air hole should be left all the way open.